The invention relates to an electrical wiring system for the drive unit in vehicles, which will be referred to in the following merely as wiring. The wiring is, in particular, destined for the drive unit, i.e. in particular for the internal combustion engine and transmission of a motor vehicle. It may, however, also be used for motorcycle engines, boat engines or aircraft engines.
Hitherto, a wiring harness has been provided in the engine compartment of a motor vehicle, which connects the functional units of the internal combustion engine and other electrical functional units within the engine compartment with each other and with the rest of the vehicle as far as the electrical power supply and the exchange of data and signals is concerned. Such functional units are, in particular, sensors, such as knock or oil level sensors, and actuators, such as injection and ignition means. Apart from electrical wires, wiring harnesses may, in particular, also include optical wires, for example optical waveguides.
Traditional wiring looms, such as shown for example in DE 3824857 and the DE 3903818, have a tree-like structure with a great variety of branches and ramifications. The production of such a wiring loom requires a large number of manual processes. Another problem is that, due to the drastically increasing number of functional units and functional contents of engines and transmissions, the wiring looms contain more and more wires and thus increase in weight and volume. Thus, the technical designers face increasing difficulties when accommodating the wiring loom in the engine compartment.
Furthermore, today, so-called electronic boxes (E-boxes) are rigidly mounted to the car body in the engine compartment and connected to the wiring loom. Such E-boxes, such as disclosed for example in WO 96/00156 and in DE 19511755, contain an increasing number of electronic control devices for the engine and its units as well as relay components. The control devices have their own casings which, in part, contain passive cooling elements. The control devices and the relays are placed within a voluminous plastic casing of the E-box with the control devices and relays connected individually via plug-type connections and plug bases directly to the wiring loom. The result is, on the one hand, that the E-box is of a considerable size, which in turn, triggers positioning problems, and on the other hand it is time-consuming to assemble due to the manual assembly of the numerous plug-in connections between the wiring loom and the E-box.
EP 0 674 100 A1 describes a system for the operation and control of sensors, apparatus and functional units of a vehicle with the electronic control device 4 being mounted at or within an air intake of an internal combustion engine. The electronic control device 4 comprises three connectors 5A, 5B, 5C, which are connected to the corresponding counter connectors 6A, 6B, 6C. These counter connectors, in turn, are connected to the corresponding bundles of electric cables 7A, 7B, 7C. The first bundle 7A is responsible for the electrical connection to the sensors, apparatus and activators in the vehicle body. The second bundle 7B is responsible for the electrical connection to the sensors, apparatus and activators in the engine. Finally the third bundle 7C is responsible for the electrical connections to the sensors, apparatus and activators in the air intake 3.
Furthermore, EP 0 857 618 A2 describes a motor control device 17 which is mounted on the engine block in a section 12D of the engine 12. Furthermore, the motor control device 17 has a circuit plate 17D with a CPU. The motor control device 17 is mounted on the engine and connected to switches and functional units by means of a traditional wiring loom (cf. column 3, lines 50 to 58).
The invention is based on the technical problem of creating an electrical wiring system for the drive unit in a vehicle in which the issue of accommodating the wiring is improved, whilst at the same time simplifying the manufacture and installation of the wiring.
This technical problem is, according to the invention, solved by an electrical wiring system with the features of point-to-point connections. The related circuits of the first and second electrical connections are made within the central distribution unit. This central distribution unit is mounted on the drive unit and comprises a control platform with at least one electronic control module.
Thanks to this wiring concept with a central circuit and electrical point-to-point connections, there are no electrical branches as in the case of the traditional wiring harness. Thus, the cable end connectors, which until now had to be produced at considerable manual effort on the wiring harness, are no longer required. In this respect, it was, for example, necessary to join certain bared cable ends manually to form a circuit, to solder them to each other (or to weld or to crimp them) and to fit them with a protective cap. In the case of the wiring that is object of the invention, connector cables are now used that can be standardized in terms of number of pins, length, conductor cross section, etc. In this respect, several electrical point-to-point connections can be spatially combined, at least in part, for example in the form of a foil wire with several electrical strip conductors that are arranged in parallel. Such individual strip conductors may, if necessary, naturally be branched off geometrically from the foil wire i.e. the foil wire mayxe2x80x94for example, by careful opening or unravelling of its foil connections between the electrical strip conductorsxe2x80x94be gradually divided into individual strip conductors so that they can be brought to the corresponding connecting points.
According to the invention, electrically non-branching point-to-point connections are provided, i.e. individual strip conductors or conductors, for example copper conductors, which do not have any electrical branches or taps. A geometrical, i.e. spatial branching or sub-division of the bundles of wires, foil wires etc. is naturally possible according to the invention, if the individual electrical conductors or strip conductors only form point-to-point connections.
Such standardized interconnections can be produced in an automated process, since the interconnections themselves no longer contain circuits. This results in corresponding production advantages, and manual production effort can be minimized in the wiring that is the object of the invention.
Also, mounting the central distribution unit on the drive unit directly in accordance with the invention and integrating the electronic control modules within the central distribution unit can considerably reduce the extent of the wiring and save wire length. The electronic control modules that correspond in functional terms to the control devices that have been customary up to the present, may now, according to the invention, be integrated without an individual casing directly on the control platform. For this purpose, the control platform is configured preferably as a fixed or flexible circuit board or FPC (flexible printed circuit) plate. It may, however, also be configured as a fixed or flexible circuit component in other suitable techniques that are known to the skilled person, for example as a printed or etched circuit board or using MID (moulded interconnect device) technology. The control platform also preferably includes the contact points and interfaces to the interconnections.
Thus, the traditional E-boxes with their numerous interfaces and slots and their considerable physical size can, according to the invention, be dispensed with. Instead, the traditional control devices with their casings can be replaced by electronic control modules that are directly installed on the control platform. The circuit of the electrical connections is linked with the electronic control systems and also made on the control platform. Thus, also numerous bulky and expensive plug-in and cable connections, which are until now required in the E-box, become obsolete. Furthermore, the labour-intensive manual connection of the wiring harness connections with the individual control devices, relay slots, etc. also becomes obsolete.
According to the invention, it was found that mounting the central distribution unit with the control electronics on the drive unit is possible. The central distribution unit is preferably mounted on an internal combustion engine or on the corresponding drive motor of the drive unit or on the accessories of the internal combustion engine or drive motor. The central distribution unit is most advantageously mounted on the air intake, or on the air filter or as an integral component of an already existing engine component or an engine accessory. Furthermore, the central distribution unit may be mounted on the manual gear box or automatic transmission of the drive unit. If the distribution unit is mounted on the engine or its accessories, this results in a completely pre-wired engine with the related control electronics which can be fully bench-tested as a free-standing unit. Thus, the motor with its wiring and control systems may, for example, be manufactured in a country other than the one in which the rest of the vehicle is manufactured and then supplied, ready to be installed, to the final assembly line as a completely function-tested module. Until now, numerous function tests could only be carried out after the installation of the wiring harness in the vehicle and after the numerous connections of the wiring harness to the E-box had been made.
The fixing of a junction box on the front part of the vehicle frame is known from EP 0 031 400 A2. The purpose of this junction box is to distribute the electrical power from the electrical power supply to the components which use the power; these include the front exterior lights of the vehicle, the hooters and the engine-related components which use electricity. In this respect, the power is merely distributed without the junction box having any additional function. No consideration has been given to a central arrangement at the drive unit.
It is more appropriate for at least a single electronic control module to take over engine control functions and/or transmission control functions. It is preferable for the control platform to carry in addition active and/or passive electrical and/or electronic components or modules, such as for example high-level power stages, relays, fuses, capacitors, resistance type suppressors, diodes or such-like that are involved or integrated in the circuits between the first and second electrical connections. Additionally, an external start connection or a high tension current connection can be configured within the central distribution unit. Moreover, plugs for diagnostic purposes may be provided.
The control platform is preferably configured in a modular way. Thus, different types of engines can be accommodated by adding or removing modular platform components. However individual modules can be changed, for repair purposes if necessary.
A clearly organized structure for the wiring results from the invention. The wiring can be built up according to the concrete requirementsxe2x80x94as if from building blocks. Thanks to this modular concept, the interconnections can be largely standardized and produced by automated processes. The result is a considerable simplification of the construction process and the manufacture of the wiring.
In case of multiple engine variants the central distribution unit may be configured to meet the maximum requirement, so that the same distribution unit can be used for the different variants without modification. For each variant fewer or different connections may be made to the distribution unit as necessary. Similarly fewer or different electrical/electronic components are placed onto the control platform depending on the variant. Variant-specific circuits may be made simply in the central distribution unit if necessary by the use of so-called jumpers.
A bus connection cable may also be used to connect the central distribution unit with the vehicle using multiplex technology. As a whole the number of first connecting wires can be minimized. As far as the electrical power supply is concerned, only a single supply wire which connects the central distribution unit with the vehicle battery is required. In contrast to the increasing thickness of the traditional wiring harness towards its base, the invention minimises the number of first connections between the vehicle and the distribution unit. These require less space and can easily be placed within the engine compartment.
Thanks to the modular concept of the invention, technical modifications of the wiring can also be carried out relatively easily by means of a corresponding modification of the distribution unit, whereas until now the complete structure of the wiring harness had to be modified.
As far as the spatial configuration of the control platform or of the central distribution unit is concerned, wiring connections which could disturb each other electromagnetically can be placed at exactly defined distances from each other so that their electromagnetic compatibility is guaranteed. The central distribution unit is responsible for a calculable and clearly defined position of the wires in relation to each other. Additionally, screening measures can be taken comparably easily in the area of the central distribution unit, for example by installing screen webs, shrouds or casings. In contrast, the different wires of the traditional wiring harnesses are contained in the harnesses in an undefined way so that the mutual influence of the wires is unclear. Due to the increasing problems of electromagnetic compatibility, expensive twisted or screened wires must often be used up to the present time, for example.
The term xe2x80x9cconnecting wiresxe2x80x9d used in this document includes a variety of other wires such as foil wires, flat strips, hybrid wires, etc. as well as sheathed copper wires, and in particular multi-purpose wires that contain data conductors and power supply conductors within a common coating. If required, even optical cables, pneumatic or fluid conductors can also be installed in the wiring. If required it is also possible to install individual wires in the form of a by-pass to the central distribution unit,
The term functional units on the engine or in the engine compartment means a wide variety of sensors, components using electrical current, actuators and the like. Such functional units connected to the distribution unit via the second connecting wires are, for example, ignition coil connections, variable camshaft controls, variable valve drive controls, knock sensors, revolution and torque sensors, lambda sensors, probes or injection valves.
The contacts between the interconnections and the central distribution unit can be made in a wide range of ways. Here, plug-in connections, clamp contacts, soldered joints, weld joints or similar contacts can be used. Thus both detachable and non-detachable connections can be considered.
The invention results in a wiring concept that is well suited for extensively automated production that can be optimised as far as the construction volume is concerned, that is flexible in terms of constructing variants and technical modifications and that is distinguished by a clearly organized wiring structure. The number of plug-in connections is reduced, and thus costs and assembly expenditure are also reduced. Thanks to the clearly organized spatial structure of the wiring that is object of the invention wiring mistakes during assembly can be reduced, i.e. another increase in quality can be achieved, and the replacement of individual interconnections can be achieved without problems. Also electromagnetic compatibility problems can be minimized, since interference-prone wires are placed far away from the corresponding sources of interference by means of a corresponding wiring configuration. Thanks to the carrier function of the central distribution unit for components with electrical and/or electronic functions, such as ignition high-stage levels, fuse switches or control devices, the number of interconnections required and the number of plug-in connections can be further optimised.
By mounting the central distribution unit on the drive unit, in particular on the engine, and by the integration of the control devices, such as the engine control devices for the ignition, injection, variable valve drive, etc. within the central distribution unit, the motor becomes a self-contained object, i.e. the engine unit can be tested separately including electrical/electronic components. A diagnostic plug can also be provided for example.
The central distribution unit can be arranged as an integral part of an already existing engine component, for example the cylinder head cover, the air intake or the air filter of the internal combustion engine. Thus, such an engine component can be used with advantage as a carrier unit and, if necessary, as protection for the positioning of the central distribution unit.
The central distribution unit is fitted if necessary with a suitable protective casing for mechanical protection against dirt, humidity, etc. and with its own active cooling system, for example a fan, for thermal protection. According to the invention, it was found that the central distribution unit can be positioned with advantage directly on the drive unit in spite of the increased temperatures caused by the internal combustion engine. The three dimensional form and arrangement of the protective casing of the central distribution unit and its internal space can be well adapted to the space available in the required location.